The present invention relates to a lithium secondary battery having a positive electrode, a negative electrode and a non-aqueous electrolyte.
A secondary battery, especially, a lithium secondary battery has lately been attracting attention as an operating power source for portable electronic equipment that can be miniaturized, is highly efficient and is cordless. A lithium secondary battery contains a positive electrode having a positive electrode active material, a negative electrode having a negative electrode active material and a non-aqueous electrolyte.
The most common and practical lithium secondary battery has a carbon material, for example, graphite or the like, as a negative electrode active material, and crystalline LiCoO2 as a positive electrode active material. A lithium secondary battery having a high voltage, i.e., 4V, and high energy density can be provided because crystalline LiCoO2 has a high voltage level.
However, reduction of consumption of power has been recently required for electronic equipment. Operating voltages of electric circuits have been gradually reduced. Therefore, a lithium battery having high discharge capacity density is required more than one having a high discharge voltage.
An object of the present invention is to provide a lithium secondary battery which has higher capacity density per volume and per weight.
The present invention provides a lithium secondary battery having positive and negative electrodes and a non-aqueous electrolyte, wherein the positive electrode contains Lixe2x80x94Bi alloy or Lixe2x80x94Sb alloy as an active material.